Problem: Simplify the following expression: $r = \dfrac{8}{2n} \times \dfrac{10n}{2}$
Answer: When multiplying fractions, we multiply the numerators and the denominators. $r = \dfrac{ 8 \times 10n } { 2n \times 2}$ $r = \dfrac{80n}{4n}$ Simplify: $r = \dfrac{20}{1}$